教師資料查詢 | 類別: 會議論文 | 教師: 楊淑君 SHU-CHUN YANG (瀏覽個人網頁)

標題:Influence of the molecular geometry on the photoexcitations of highly emissive organic semiconductors
學年88
學期1
發表日期1999/12/17
作品名稱Influence of the molecular geometry on the photoexcitations of highly emissive organic semiconductors
作品名稱(其他語言)
著者Yang, Shu-chun; Graupner, W.; Guha, S.
作品所屬單位淡江大學物理學系
出版者SPIE-The international society for optical engineering
會議名稱Proceedings of the SPIE v.3797, Organic light-emitting materials and devices III
會議地點Bellingham, WA, USA
摘要Para-phenylene type molecules are efficient photoluminescence emitters in the ultraviolet-blue-green spectral range. They are used in light emitting diodes (LEDs) and photopumped lasers. Photoexcited para-phenylene type molecules give rise to strong emission from singlet excitons, bleaching of the singlet exciton absorption, induced absorption from triplet excitons and induced absorption from polarons. Since the latter two processes represent absorption of the emitted light of singlet excitons, the presence of polarons and triplet excitons might be a fundamental problem for laser diodes made from para-phenylene type molecules. In our experiments we modify the molecular geometry by the application of hydrostatic pressures up to 80 kbar in a temperature range of 10 to 300 K. In particular we show how triplet and polaron states, which are present in LEDs under operation, react to the induced geometric changes. The spectra of ground state absorption, excited state emission, bleaching of the singlet exciton absorption, induced absorption from triplet excitons and induced absorption from polarons are significantly broadened and shifted in energy. In order to explain the observed behavior we have performed three-dimensional bandstructure calculations within density functional theory for the planar poly(para-phenylene). By varying the intermolecular distances and the length of the polymer repeat unit pressure effects can be simulated.
關鍵字
語言英文
收錄於
會議性質國際
校內研討會地點
研討會時間19991217~19991217
通訊作者
國別美國
公開徵稿Y
出版型式紙本
出處Proceedings of the SPIE v.3797, Organic light-emitting materials and devices III,pp.26-37
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